import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    static int minimumNumber(int n, String password) {
        
        boolean digit = false, upper = false, lower = false, symbol = false;
        int constraints = 0;
        
        for(char c : password.toCharArray()) {
            if(!digit && Character.isDigit(c)) {
                digit = true;
                constraints++;
            } else if(!upper && Character.isUpperCase(c)) {
                upper = true;
                constraints++;
            } else if(!lower && Character.isLowerCase(c)) {
                lower = true;
                constraints++;
            } else if (!symbol && isSymbol(c)) {
                symbol = true;
                constraints++;
            }
        }
        
        int answer = 0;
        if (constraints == 4) {
            if(n < 6) {
                answer = 6 - n;
            }
        } else {
            answer = 4 - constraints;
            if((answer + n) < 6) {
                answer += 6 - (answer + n);
            } 
        }  
        return answer;
    }
    
    public static boolean isSymbol(char c ) {
        return c == '!' || c == '@' || c == '#' || c == '$' || c == '%' || c == '^'
            || c == '&' || c == '(' || c == ')' || c == '-' || c == '+';
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        String password = in.next();
        int answer = minimumNumber(n, password);
        System.out.println(answer);
        in.close();
    }
}